1. Field of the Invention
The present invention relates to radiolucent surgical tables and, more particularly, to a radiolucent surgical table with a low radiographic shadow edge profile, a plurality of clamp systems for connection onto the edge profile, and a set of surgical accessories integrated with the clamps.
2. Description of the Prior Art
Conventional surgical tables include a flat patient support and a lower base for holding the patient support a predetermined distance from the floor. The base of conventional surgical tables commonly includes control apparatus for tilting the flat patient support through a range of orientations to facilitate performance of certain surgical procedures. Typical flat patient supports are made of surgical stainless steel and in most cases include a set of metal side rails supported along the edges of the table for holding surgical accessories, instrumentation, and the like. Typically, the side rails conform to an industry standard cross sectional size and configuration so that surgical accessories from any vendor source can be directly connected to surgical tables built by another vendor without modification of the attachment interface.
One disadvantage of stainless steel table tops of the type described above is that they block x-rays. Accordingly, their use in surgical or interventional procedures that require x-rays, fluoroscopic or other patient images to be taken are quite limited.
As a result, patient support tables have been proposed that utilize an x-ray translucent material, such as phenolic resins, in selected portions of the table top. The x-ray translucent material allows interoperative x-ray image signals to be generated using fluoroscopic devices, C-arm or CT scanners and other imaging equipment.
One such example of a prior art radiolucent table is shown at FIG. 1. As illustrated in cross section, the flat patient support 10 includes a substantially planar table top member 12 formed of a x-ray translucent material such as, for example, a carbon fiber material or a phenolic resin such as sold under the trade name SPAULDITE. Due mainly to load carrying capacity limitations and to enhance stiffness, the table top 12 is supported on either side by a pair of longitudinally extending metal frame members 14, 16. Each of the metal frame members 14, 16 are attached to the bottom surface of the table top member 12 using a suitable cement such as an epoxy, fasteners, or the like. A pair of side rail members 18, 20 are held in a fixed relationship relative to the metal frame members 14, 16 as illustrated. The side rail members 18, 20 have a size and shape that conform to the industry-wide standards noted above.
One disadvantage of the flat patient support 10 illustrated in FIG. 1 is that the metal frame members 14, 16 as well as the side rail members 18, 20 generate shadows when the patient support 10 is used in radiographic imaging procedures. As a result, only the portion of the radiopaque table top member 12 that is disposed between the pair of metal frame members 14, 16 is usable for radiographic imaging. This limitation becomes more pronounced when the table is tilted relative to the x-ray generator. The angle of the table relative to the x-ray source effectively shortens the distance between the metal side frame members 14, 16 as viewed from the x-ray source thus reducing the shadow-free areas in the radiographic image.
FIG. 2 illustrates another prior art surgical table configuration that is somewhat useful in radiographic imaging and in certain interventional procedures. As shown there, a predominant feature of the flat patient support 22 is a relatively thick slab 24 of radiographic material having a generally rectangular cross section. The slab 24 is provided on opposite transverse edges 26, 28 with a substantially square accessory interface profile 30, 32 as shown. Each of the accessory interface profiles 30, 32 are sized and shaped to receive a pair of accessory coupler members 34, 36 on the opposite transverse edges 26, 28 of the radiopaque slab 24. In turn, each coupler member 34, 36 carries an industry standard side rail member 18, 20 of the type described above. In that way, most commercially available accessories can be used with the table.
One drawback to the xe2x80x9cslabxe2x80x9d type radiolucent surgical tables shown in FIG. 2 is that the accessory coupler members 34, 36 are typically formed of metal and therefore obstruct x-ray signal propagation through portions of the table along the table edges. As a result, undesirable shadows are formed in the radiographic image.
Simple removal of the accessory coupler members 34 or 36 does not completely-solve the shadow problem. The vertical surfaces along the square edges of the accessory interface profiles 30, 32 lead to shadows in radiographic images. The shadows are caused because, during normal use of the table, the vertical edges of the profile are typically aligned in a substantially parallel relationship with x-ray signal propagation. As a result, the edge surfaces tend to attenuate the x-ray signal to a substantial degree greater than the flat horizontal surfaces and, accordingly, the vertical edge surfaces generate shadows in the radiographic image.
It is, therefore, desirable to provide a radiolucent surgical table that presents a substantially uniform attenuation characteristic to x-ray signals in both the lateral and transverse directions and with the table held flat or tilted relative to the x-ray signal source. In that way, the radiographic images of a patient disposed on such surgical table would be free and clear of extraneous shadows.
Copending application Ser. No. 09/804,287 filed on Mar. 12, 2001 and assigned to the assignee of the instant application provides such a table. In addition to being substantially x-ray shadow free overall, a surgical accessory interface profile is provided so that a wide range of surgical accessories can be easily and directly connected anywhere along the edge of the table top. The accessory interface profile presents a substantially uniform attenuation characteristic to x-rays passing through the table top and table top edges regardless of the angle of the table top relative to the x-ray source.
There is a need, therefore, for providing a set of clamp apparatus for connecting a plurality of medical accessories onto the interface profile of the radiolucent table. Preferably the clamp modalities are selected based on intended use with specific medical accessories and, in that way, the clamps provide the desired support for the medical accessories with which they are paired for ease of use, reduction in cost and to minimize size.
In accordance with the present invention, therefore, a shadow free radiolucent patient support table is provided including substantially planar top and bottom surfaces held apart in an opposed relationship. The radiolucent patient support table is preferably formed of an outer layer of carbon fibers surrounding an inner foam core. The outer longitudinal edges of the support table define a substantially continuous medical appliance support interface for selectively connecting a plurality of associated medical appliances to the table. The medical appliance support interface generally comprises a non-planar first connection area defined on the top surface of the surgical table and a second connection area defined on the side of the table top. The non-planar first connection area is shaped to provide first and second static supporting forces against an associated medical appliance, when connected to the table, in directions substantially parallel to and perpendicular with the top and bottom surfaces of the table. The second connection area is shaped to provide third and fourth static supporting forces against the associated medical appliance in third and fourth directions substantially parallel to and perpendicular with the top and bottom surfaces. The first and third forces cooperate to support a load moment generated by the medical accessory held by the table edge. The second and fourth forces cooperate to support the medical accessory against gravity and in a vertical direction.
In accordance with one aspect of the invention, the non-planar first connection area includes a curved lip surface extending along the upper edge of the table top and at least one recess defined between a pair of wall surfaces that converge at a bight region of the at least one recess. The lip and recess are preferably formed as a continuous smoothly curved surfaces disposed along the outer longitudinal edges of the table top.
In accordance with yet another aspect of the invention, the second connection area includes a substantially planar surface held at an oblique angle relative to the substantially planar top and bottom surfaces. The planar surface of the second connection area forms an acute angle with the top surface of the table and forms an obtuse angle with the bottom surface of the table. In that way, the second connection area generates a static counter-force against the associated medical appliance connector in a downward direction relative to the table top so that a downwardly directed lip formed on the connector is forced into tight engagement with the at least one recess defined by the first connection area.
In accordance with a still further aspect of the present invention, a segmented medical appliance connector is provided for attaching a wide range of surgical accessories directly to the table top at selected positions along the interface profile. The connector includes movable upper and lower jaws that are adapted to clamp onto the interface profile.
In accordance with still yet a further aspect of the invention, a unitary appliance connector is provided for attaching surgical accessories to the table top. The unitary connector includes a resilient engagement area that is adapted to be press-fitted onto the interface profile of the table top. The unitary connector has no moving parts and therefore is easy to use and can be sterilized conveniently.
In accordance with still yet a further aspect of the invention, a clamping apparatus for securing an associated accessory to an outer edge of an associated patient support member is disclosed. The outer edge of the patient support member has a top recess and an essentially planar and non-vertical side surface slanting inwardly from top to bottom and terminating in a flared lower edge extending beyond the bottom of the patient support member. The clamping apparatus includes an upper jaw member which has a downwardly projecting lip formed to essentially conformably engage a section of the top recess of the patient support member. A lower jaw member is also included and has a hook region formed to surroundingly engage a section of the flared lower edge of the patient support member. A means is provided for joining the upper and lower jaw members.
In one aspect of the clamping apparatus, the means for joining comprises a direct connection between the upper and lower jaw members whereby the upper jaw member, the lower jaw member, and the direct connection form a single unitary piece made from a resilient material. Preferably, the clamping apparatus further includes a spring which is at least partially embedded in the upper jaw member and essentially conforms with the lip area whereby an associated accessory may be supported in a flexible manner by the clamping apparatus. The spring may optionally extend outside the unitary piece in an upward direction to provide a flexible hook for attaching the associated accessory.
In another aspect of the clamping apparatus, the means for joining comprises a hinge region with a pivot axis about which the upper and lower jaw members may relatively pivot. The joining also includes a means for effectuating closure of the upper and lower jaw members whereby the clamping apparatus firmly clamps to a portion of the outer edge of the patient support member.
It is a primary object of the invention to provide a radiolucent surgical table that presents a substantially uniform attenuation characteristic over the entire surface area of the table top in both lateral and transverse table top directions with the table held flat or tilted relative to the x-ray source.
It is another object of the invention to provide such a table top that includes an accessory interface profile along the edge of the table top so that various surgical accessories, instruments, and the like can be quickly and easily attached to the radiolucent table as needed. The accessory interface edge profile presents a substantially uniform x-ray attenuation characteristic because it is formed without flat surfaces in alignment with the x-ray propagation direction. Essentially all of the surfaces of the interface edge profile are curved, rounded, or flat and disposed at oblique angles relative to the x-ray propagation direction.
It is another object of the invention to provide a radiolucent surgical table with a low shadow accessory interface profile that is convertible for use in a wide range of surgical and interventional procedures by providing a set of intermateable table top portions that are selectively arranged and fastened together into various configurations as needed. Preferably, the table top portions are connected using simple pin type attachment mechanisms.
It is yet another object of the invention to provide medical appliance connectors that are adapted to cooperate with the interface profile defined in the surgical table top to support various surgical devices and instruments relative to the table.
These and other objects and benefits of the present invention will be described below.